 namespace local = ""
 namespace inh = inherit
 
 start = 
    element library
    {
       element book
       {
          attribute id { text },
          attribute available { text },
          element isbn { text },
          element title { attribute xml:lang { text }, text },
          extra-book-content*
       }+
    }
 
 extra-book-content |= 
    element author
    {
       attribute id { text },
       element name { text },
       element born { text },
       element dead { text }?
    }
 
 extra-book-content |= 
    element character
    {
       attribute id { text },
       element name { text },
       element born { text },
       element qualification { text }
    }
